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rcuwait: Add @state argument to rcuwait_wait_event() 

Extend rcuwait_wait_event() with a state variable so that it is not
restricted to UNINTERRUPTIBLE waits.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200321113241.824030968@linutronix.de
This commit is contained in:
Peter Zijlstra (Intel) 2020-03-21 12:25:55 +01:00 committed by Peter Zijlstra
parent d964ea7014
commit 80fbaf1c3f
2 changed files with 11 additions and 3 deletions
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12
include/linux/rcuwait.h
View File

@ -3,6 +3,7 @@
#define _LINUX_RCUWAIT_H_ #define _LINUX_RCUWAIT_H_
#include <linux/rcupdate.h> #include <linux/rcupdate.h>
#include <linux/sched/signal.h>
/* /*
* rcuwait provides a way of blocking and waking up a single * rcuwait provides a way of blocking and waking up a single
@ -30,23 +31,30 @@ extern void rcuwait_wake_up(struct rcuwait *w);
* The caller is responsible for locking around rcuwait_wait_event(), * The caller is responsible for locking around rcuwait_wait_event(),
* such that writes to @task are properly serialized. * such that writes to @task are properly serialized.
*/ */
#define rcuwait_wait_event(w, condition) \ #define rcuwait_wait_event(w, condition, state) \
({ \ ({ \
int __ret = 0; \
rcu_assign_pointer((w)->task, current); \ rcu_assign_pointer((w)->task, current); \
for (;;) { \ for (;;) { \
/* \ /* \
* Implicit barrier (A) pairs with (B) in \ * Implicit barrier (A) pairs with (B) in \
* rcuwait_wake_up(). \ * rcuwait_wake_up(). \
*/ \ */ \
set_current_state(TASK_UNINTERRUPTIBLE); \ set_current_state(state); \
if (condition) \ if (condition) \
break; \ break; \
\ \
if (signal_pending_state(state, current)) { \
__ret = -EINTR; \
break; \
} \
\
schedule(); \ schedule(); \
} \ } \
\ \
WRITE_ONCE((w)->task, NULL); \ WRITE_ONCE((w)->task, NULL); \
__set_current_state(TASK_RUNNING); \ __set_current_state(TASK_RUNNING); \
__ret; \
}) })
#endif /* _LINUX_RCUWAIT_H_ */ #endif /* _LINUX_RCUWAIT_H_ */

2
kernel/locking/percpu-rwsem.c
View File

@ -234,7 +234,7 @@ void percpu_down_write(struct percpu_rw_semaphore *sem)
*/ */
/* Wait for all active readers to complete. */ /* Wait for all active readers to complete. */
rcuwait_wait_event(&sem->writer, readers_active_check(sem)); rcuwait_wait_event(&sem->writer, readers_active_check(sem), TASK_UNINTERRUPTIBLE);
} }
EXPORT_SYMBOL_GPL(percpu_down_write); EXPORT_SYMBOL_GPL(percpu_down_write);